One or more embodiments of the disclosed technology relate to a backlight scanning method for a liquid crystal display and a liquid crystal display.
Liquid crystal displays (LCDs) suffer from two main shortcomings in application to televisions: severe motion artifacts (which occur when displaying moving scenes or an action movie) and inadequate contrast (in a dark field condition). A black frame insertion technology is a common technology for shortening a response time. A fast pulse modulation effect similar to that in cathode ray tube (CRT) display can be produced by interpolating a black frame for every image frame. A flickering light-emitting diode (LED) backlight can also produce an effect similar to the insertion of a black frame, and it achieves the black frame insertion effect by regularly turning off the backlight. Furthermore, a good effect can also be obtained by a backlight scanning method for driving the backlight in a pulse modulation manner. One of current trends is to combine these fast response technologies so as to attain a shorter gray-to-gray response time.
FIG. 1 shows a schematic view showing the principle of improving a motion smear (streaking) by backlight blinking and backlight scanning, where an LED backlight is turned on or off at a proper place of a liquid crystal response curve. The backlight is turned off when the liquid crystal response curve is in a slow ascending phase or a descending phase (a tailing phase), and is turned on when the liquid crystal response curve is in a stable phase. To realize a backlight source employing a backlight scanning technology and also ensure lightness and thinness, a side-light type backlight scanning technology has become a hot research concern. A difficulty in application of the side-light type backlight scanning technology lies in that it is necessary to assure that the light in a region radiated by an LED group will not diffuse into other regions and ensure that a corresponding LED group is turned on in the stable response phase of liquid crystals in pixels. It is important to ensure that a corresponding LED group is in an off-state in the stable response phase of liquid crystals in pixels, so that pixels not in the stable response phase are imperceptible by human eyes.